In on-vehicle navigation apparatuses, portable information devices such as PDAs (Personal Digital Assistants) and cellular phones, and personal computers according to related art, it is possible to store map information on roads such as ordinary roads and highways, names of facilities, and so forth in various storage devices or to download such map information from a server or the like in order to show a map of a desired area to a user.
In recent years, various types of electric drive vehicles have been provided, such as electric vehicles in which a motor driven by electric power supplied from a battery is used as a drive source and hybrid vehicles in which a motor and an engine are used in combination as drive sources. In general, the battery of the electric drive vehicle is charged at home or at a dedicated charge facility. However, compared to refilling an engine with gasoline or other fuel, the electric drive vehicle requires a long time for battery charging in order to be supplied with an amount of energy required for traveling the same distance. Thus, when the remaining amount of the battery is low, drivers often prefer to charge the battery only by an amount required for the trip to be made, and not up to full amount. Thus, for electric drive vehicles in which a motor is used as a drive power source, it is important to inform the user of how far the vehicle can travel for a charge time of the battery, that is, a range in which the vehicle can travel (hereinafter referred to as a “travelable range”) before electric power accumulated in the battery after being charged for a predetermined charge time is used up (with combined use of an engine in the case of hybrid vehicles).
With this in view, related art proposes to provide the user with a travelable range based on the charge time described above using a device having a map display function such as a navigation apparatus. For example, Japanese Patent Application Publication No. JP-A-2003-294463 describes a navigation apparatus for an electric vehicle that allows the user to input a desired battery charge time and displays a travelable range of the vehicle corresponding to the input charge time.
Patent Document 1: Japanese Patent Application Publication No. JP-A-2003-294463 (page 5, FIG. 14)